Background

The French Fields project was a private self build residential development located in a rural setting in Wiltshire. As with many low density residential schemes, managing surface water runoff sustainably on site was a key requirement, particularly where connections to traditional drainage infrastructure were limited.

The homeowner sought a solution that would meet planning and environmental requirements while fitting discretely within the landscape and maintaining long term performance with minimal maintenance.

The challenge

The drainage strategy needed to:

  • Comply with SuDS principles, managing water at source
  • Accommodate runoff from roofs and hardstanding areas
  • Avoid discharge to overloaded or unavailable sewer networks
  • Be installed efficiently within a self build programme
  • Provide sufficient storage without impacting usable space

Traditional attenuation tanks or open SuDS features were not considered appropriate for the site constraints and aesthetic requirements of the scheme.

The solution

Marshalls supplied its Permavoid stormwater management system, providing a modular, below ground attenuation solution designed to manage surface water runoff close to where it falls.

Permavoid units were installed below ground to create a high void storage structure, allowing rainwater to be temporarily held and released at a controlled rate in line with SuDS best practice. The modular nature of the system provided flexibility in layout and sizing, enabling the system to be tailored to the specific hydrological needs of the site.

The solution allowed surface water from impermeable areas to be managed on site without the need for large excavation, concrete tanks, or visible drainage features.

The outcome

The Permavoid system delivered a discreet, effective and sustainable drainage solution for the self build project.

  • On site attenuation reduced flood risk
  • Full compliance with SuDS requirements
  • Flexible installation suited to a self build programme
  • Below ground solution preserved aesthetics and usable space
  • Long term, low maintenance stormwater management

The French Fields project demonstrates how modular SuDS systems can be successfully applied to small scale residential developments, offering the same engineering robustness as larger infrastructure schemes in a compact form.